用户指南和参考

ST_PointFromWKB

ST_PointFromWKB 接受点类型的公认二进制表示和 Spatial 参考系标识,并返回点。

语法

db2gse.ST_PointFromWKB(WKBPoint Blob(1M), srs SRID)

返回类型

db2gse.ST_Point

示例

以下代码段填充 HAZARDOUS_SITES 表。

危险地点存储在用以下 CREATE TABLE 语句创建的 HAZARDOUS_SITES 表中。 定义为点的 LOCATION 列存储每个危险地点的地理中心的位置。

CREATE TABLE HAZARDOUS_SITES (site_id   integer,
                              name      varchar(128),
                              location  db2gse.ST_Point);
 
/* Create the SQL insert statement to populate the site_id, name and
   location. The question marks are parameter markers that indicate the
   site_id, name and location values that will be retrieved at runtime. */
strcpy (wkb_sql,"insert into HAZARDOUS_SITES (site_id, name, location)
values (?,?, db2gse.ST_PointFromWKB(cast(? as blob(1m)),
db2gse.coordref()..srid(0)))");
 
/* Allocate memory for the SQL statement handle and associate the
   statement handle with the connection handle. */
rc = SQLAllocStmt (handle, &hstmt);
 
/* Prepare the SQL statement for execution. */
rc = SQLPrepare (hstmt, (unsigned char *)wkb_sql, SQL_NTS);
 
/* Bind the site_id integer value to the first parameter. */
pcbvalue1 = 0;
rc = SQLBindParameter (hstmt, 1, SQL_PARAM_INPUT, SQL_C_INTEGER,
     SQL_INTEGER, 0, 0, &site_id, 0, &pcbvalue1);
 
/* Bind the name varchar value to the second parameter. */
pcbvalue2 = name_len;
rc = SQLBindParameter (hstmt, 2, SQL_PARAM_INPUT, SQL_C_CHAR,
   SQL_CHAR, 0, 0, name, 0, &pcbvalue2);
 
/* Bind the location shape to the third parameter. */
pcbvalue3 = location_len;
rc = SQLBindParameter (hstmt, 3, SQL_PARAM_INPUT, SQL_C_BINARY,
     SQL_BLOB, location_len, 0, location_wkb, location_len, &pcbvalue3);
 
/* Execute the insert statement. */
rc = SQLExecute (hstmt); 


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